Solid oxide fuel cells (SOFCs) have the potential to convert the chemical energy in fuels, including hydrocarbon fuels, directly to electricity as schematically shown in FIG. 1. However, the cost of current SOFC systems is still prohibitive for wide-spread commercial deployment. Reducing the operating temperature of the current SOFC systems to 400-600° C. can dramatically reduce the cost of the SOFC technology since relatively inexpensive metallic components can be used for interconnects, heat exchangers, manifolding and other structural components of the SOFC system. Lowering the operation temperature can also offer quick start-up ability, which in turn can enable their use in applications such as transportable power sources and auxiliary power units for automobiles. A lower operating temperature would also ensure a greater overall system stability and durability due to a reduction in the thermal stresses in the active ceramic structures, leading to a longer expected lifetime for the SOFC system.
Eliminating the external hydrocarbon reforming system that generates hydrogen, and directly utilizing hydrocarbon fuels on the anode will increase SOFC efficiency while decreasing the complexity and cost of the SOFC system. However, the current state-of-the-art Ni-based anode deactivates rapidly with direct utilization of hydrocarbon fuels due to carbon deposition on the Ni catalyst surface. Further, SOFC performance becomes unacceptably low at reduced temperature with conventional SOFC technology. However, by controlling the microstructure of the electrode, it is possible to achieve high cell performance at reduced operating temperature and to utilize Ni-based anode materials for direct hydrocarbon oxidation.
In view of the above, a need exists for high performance low temperature direct-hydrocarbon SOFCs.